7 Brain Teasers to Ace Job Interviews

A recent CNN article explains well why a growing number of companies use brainteasers and logic puzzles of a type called "guesstimations" during job interviews:

"Seemingly random questions like these have become commonplace in Silicon Valley and other tech outposts, where companies aren't as interested in the correct answer to a tough question as they are in how a prospective employee might try to solve it. Since businesses today have to be able to react quickly to shifting market dynamics, they want more than engineers with high IQs and good college transcripts. They want people who can think on their feet."

What are technology companies (Google, Microsoft, Amazon) and consulting companies (McKinsey, Boston Consulting Group, Accenture...) looking for? They want employees with good so-called Executive Functions: problem-solving, cognitive flexibility, planning, working memory, decision-making, even emotional self-regulation (don't try to solve one of these puzzles while being angry, or stressed out).

Want to try a few? Below you have our Top 7 Guesstimations/ Logic Puzzles for Job Interviews and Brain Challenge:

Please try to GUESS the answers to the questions below based on your own logical approach. The goal is not to find out (or Google) the right answer, but to 1) identify the logic approach that will help "guesstimate" an appropriate range, say + or - 50% of the actual answer, and then 2) complete the calculations (ideally mentally, but you can also take notes) to provide an estimate.

Ready. Set. Go!

1) How many times heavier than a mouse is an elephant?.

2) How many firefighters are there in San Francisco?.

3) How many trees are there in NYC's Central Park?.

4) How many shoes have you had in your life?.

5) How many golf balls can fit in a school bus?.

6) In 1999, how were these baby boy names ranked by popularity: Kevin, Jose, Hugh.

7) What is the weight of a large commercial airplane?.

The Answer appear below. Again, the key here is to try, plan the steps towards the solution, and do the mental calculations to find a reasonable range. That's the brain challenge. The goal is not to find the precise correct answer.

Answers:

1) Around 150,000. An average elephant weighs 4,000 kg on average; an average mouse 25 grams.

2) Around 350 firefighters on duty on any given day, out of a pool of 1700 firefighting overall staff.

3) There are over 26,000 trees (of approximately 175 species) in the Park.

4) We don't know (or need to know) how many pairs you have had.

5) About 500,000, assuming the bus is 50 balls high, 50 balls wide, and 200 balls long.

6) Rankings of baby boy names in 1999, according to Social Security Administration: 1. Jose (#30), 2. Kevin (#32), 3. Hugh (#830).

7) For a Boeing 747:
- Empty: around 400,000 pounds (lbs), or 181 metric tons
- Maximum Takeoff Weight: around 825,000 pounds, or 374 metric tons
- For context, the weight of an empty Hummer is 8,600 pounds.

Some Context on Executive Functions:

If you want to learn more about what they are, here are some quotes from my Interview with neuropsychologist Dr. Elkhonon Goldberg on cognitive fitness:

Alvaro Fernandez: "Please tell us more about what the Frontal Lobes are."

Elkhonon Goldberg: "We researchers typically call them the Executive Brain. The prefrontal cortex is young by evolutionary terms, and is the brain area critical to adapt to new situations, plan for the future, and self-regulate our actions in order to achieve long-term objectives. We could say that that part of the brain, right behind our forehead, acts as the conductor of an orchestra, directing and integrating the work of other parts of the brain".

"I provide a good example in The Executive Brain book, where I explain how I was able to organize my escape from Russia into the US. Significantly, the pathways that connect the frontal lobes with the rest of the brain are slow to mature, reaching full operational state between ages 18 and 30, or maybe even later. And, given that they are not as hard-wired as other parts of the brain, they are typically the first areas to decline".

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Ready for that job interview now (on either end of the table)? In case they help, here you have more brain teasers.

Note: I have made a couple of corrections based on a comment below. Thank you, Ben!

Comments

[wm1066]

here are my answers
I. The same ratio as Godzilla to Bambi
2.Not enough
3. I love Central Park
4.That pair of Earth shoes were one too many
5.Its not the golf balls but the how many goof balls in the back of the bus
6.Who cares
7.One screaming baby too much

[AlvaroF]

If the job was for Creative at an advertising agency, or for Senator, you would have aced it :-)

[benlevi]

Well, I'm not sure I'd hire Mr. Hernandez, based on the accuracy of his blog (but then again, blogs aren't edited like newspaper articles, are they?).
The answers to #s 5 & 6 above are swapped... a minor thing.
However, the answer to #7 is definitely needing some left-brained error correction. He wrote:
7) For a Boeing 747:
- Empty: around 400,000 pounds (lbs), or 181,000 metric tons
- Maximum Takeoff Weight: around 825,000 pounds, or 374,000 metric tons

According to my intuitive calculator, 400,000 lbs. is 181 metric tons, not 181,000. Same with 825,000 lbs... 374 metric tons, not 374,000. (FYI, I intuited 100 tons, so I'd probably fail the brain challenge, too. ;-)

[AlvaroF]

Dear Ben,

When you write "Mr. Hernandez", you are probably referring to someone else, correct :-)

I will make the corrections you pointed out, than you!

PS1: please never offer me an accounting job.

PS2: the executive function is to correct mistakes and learn from them...not to never make them

[wolfgangmo]

Like most HR interview questions, these seem much ado about nothing.

I am sure that some experts will claim that 'these' questions are valid and espouse metrics to back their opinion up, but in the end no screening will tell you the mettle or compatability of your hires.

[AlvaroF]

Dear Wolfgang, these questions are less about "compatibility" and more about raw ability, at least for specific types of jobs.

And even them help detect "compatibility". For example, you can easily spot a different attitude at work here: Ben challenges me with data, and clearly corrects the matter. You choose not to engage, but to simply criticize with an easy "much ado about nothing."

Don't you think the questions/ teasers can similarly help bring to surface different abilities and attitudes? They are simply one more tool (not THE ONLY tool) to consider for interviews (and, if someone is looking for jobs in the companies listed above, prepare for) .